TUSCALOOSA — One-third of the way through spring practice and Alabama head coach Nick Saban wants to see more “conviction” and accountability from his defense.

“I think we’ve got a little more knowledge and experience and leadership on offense. I think we’re making progress defensively,” Saban said Tuesday following the team’s sixth spring practice. “We’re looking for players who can play to this standard. And we’re talking about intangibles here now, we’re not talking about ability. We’re talking about guys that will give effort, play with toughness, finish plays. Mental and physical toughness when things get difficult.”

While the Crimson Tide offense has several key players returning from last year’s team, including senior running back Damien Harris, junior starting quarterback Jalen Hurts and four of last year’s starting offensive linemen, Alabama’s defense is still a work-in-progress.

Along with trying to replace its entire starting secondary after six defensive backs either graduated or left early for the NFL, the Tide defense is searching for leadership from a unit that only returns three total starters.

Rising senior defensive end Isaiah Buggs is one of those returning starters, and acknowledged last week that coaches have expressed a desire for him to establish himself as more of a leader this spring.

“Being an experienced player now, I have to take a leadership role,” Buggs said. “All of the coaches and players are looking up to me to become the leader I need to be to help this team win and be successful for the next season.”

Among Alabama’s most questionable defensive positions right now is at nose guard, where the Tide lost both its starter (Da’Ron Payne) and backup (Joshua Frazier) from last year’s team.

Sophomore defensive end Quinnen Williams has seen some work with the first-team line at nose guard, Saban said, while a pair of 300-pound youngsters in redshirt freshman Phidarian Mathis and early enrollee Stephon Wynn Jr. have each shown progress at the position as well.

Saban also confirmed the team signed 350-pound junior college nose guard Tevita Musika last week, and he could be an option to help the team once he arrives later this summer with the rest of the 2018 summer enrollees.

“We have played Quinnen (Williams) there some, and we think he could be a good player there,” Saban said. “We have two young players that are freshmen (Mathis and Wynn Jr.) that I think both can develop into being pretty good players there. And we signed a junior college nose guard (Musika) the other day that will help us probably in the fall too.”